The present invention relates to an apparatus for driving a plurality of electrical loads of a vehicle by feeding electricity to the loads from a single power source.
An apparatus for driving electrical loads of a car, for example, is disclosed in JP-A-77680/1993.
The disclosed apparatus estimates a permissible supply power of a battery and a total consumption power of electrical loads, and regulates the power fed to loads of a lower functional priority, such as a rear defogger, a sheet heater, and so forth.
Even if the above-mentioned apparatus is used, a large current, referred to as a rush current, is needed on starting an electrical load. Therefore, nevertheless the fed power for loads of a lower functional priority is stopped, engine speed decreases in response to the generator's increasing its generated power output, and the load on the engine rapidly increases, on starting of the electrical loads. That is, the existing apparatus causes the engine speed to rapidly change when the electrical loads are started.
The present invention has been achieved in consideration of the above-described problem, and is aimed at providing an apparatus for driving electrical loads of a car, in which the engine speed does not rapidly change, even if operational states of an electrical load change.
To attain the above-mentioned objective, the present invention provides an apparatus for driving electrical loads of a car, comprising:
a plurality of direction devices comprising load switches, each of the direction devices being provided at one of a plurality of electrical loads arranged at the car, for directing an ON/OFF state of the one of the plurality of electrical loads; PA1 storage apparatus or a memory for storing an increase rate per unit time of power feeding (hereafter referred to a power feeding increase rate) preset for each of the plurality of electrical loads when a corresponding one of the direction devices indicates a state transition from an OFF state to an ON state; PA1 a plurality of drive devices comprising an output front stage transistor and an output driving stage transistor, each of the drive devices being provided at each of the plurality of electrical loads, for feeding power to the one of the plurality of electrical loads and for changing the amount of a power fed to the one from a power source; and PA1 control apparatus comprising a CPU for checking an operational state of each of the plurality of electrical loads, and, if the control apparatus has judged that at least one of the direction devices has indicated the state transition, sending such a control signal to a corresponding one of the drive devices that power is fed to a corresponding one of the electrical loads from the power source, with a power feeding increase rate preset and stored in the storage-apparatus, corresponding to the electrical load.
In the above-mentioned apparatus for driving the electrical loads, further, the storage apparatus stores a minimum ratio of power feeding (hereafter referred to a minimum power feeding ration) preset for each of the plurality of the electrical loads, which is kept even at a OFF state of a corresponding one of the direction devices, and the control apparatus sends such a control signal to a corresponding one of the drive devices that power is fed to a corresponding one of the electrical loads from the power source, which is at a stopping state, with a minimum power feeding ratio preset and stored in the storage apparatus, corresponding to the electrical load at the stopping state.
In the above-mentioned apparatus for driving the electrical load, further, an engine state detector comprising a key switch, an accelerator opening sensor and an engine revolution speed sensor for detecting an operational state of an engine of the car is included. The storage apparatus stores a power feeding increase rate preset for each of the plurality of electrical loads, according to each of the predetermined operational states of the engine, and the control apparatus or CPU checks a switching state of each of the plurality of direction devices. If the control apparatus judges that at least one of the direction devices has indicated the state transition, it sends such a control signal to a corresponding one of the drive devices that power is fed to a corresponding one of the electrical loads from the power source, with a power feeding increase rate preset and stored in the memory, corresponding to the electrical load and according to an operational state of the engine detected by the engine state detector.
In the above-mentioned apparatus for driving the electrical loads, the engine state detector includes an engine starting state detector for detecting whether the engine is at a starting state, the storage apparatus stores data indicating whether power is to be fed to each of the plurality of electrical loads, depending on functional importance of a corresponding one of the electrical loads, when a corresponding one of the direction devices directs driving of the corresponding one of the electrical loads at the starting state of the engine, and the control apparatus determines whether power is to fed to one of the plurality of electrical loads, of which driving is directed by one of the direction devices, and sends such a control signal to a corresponding one of the drive devices that power feeding to the corresponding one of the electrical loads is stopped if the control apparatus determines it is not necessary to feed power to the electrical load. Power feeding to the corresponding one of the electrical loads is continued if the control apparatus determines it is necessary to feed power to the electrical load, by referring to the data stored in the memory.
In the above-mentioned apparatus for driving the electrical loads, further, the engine state detector includes an accelerator operating amount detector for detecting an operation amount of an accelerator pedal operated by an operator, the storage apparatus stores a decrease rate per unit time of power feeding (hereafter referred to a power feeding decrease rate) preset for each of the plurality of electrical loads if an acceleration required by an operator exceeds the predetermined value, and the control apparatus estimates the acceleration required by an operator based on the operation amount of the accelerator pedal detected by the accelerator operating amount detector, and sends such a control signal to a corresponding one of the drive devices that power is fed to one of the plurality of electrical loads, of which driving is directed by one of the direction devices, with a power feeding decrease rate preset and stored in the storage apparatus, corresponding to the electrical load.
In the above-mentioned apparatus for driving the electrical loads, a fuel amount detector is provided for detecting a residual fuel amount left in a fuel tank of the car, the storage apparatus stores a decrease rate per unit time of power feeding (hereafter referred to a power feeding decrease rate) preset for each of the plurality of electrical loads, the power feeding decrease rate for each of the plurality of electrical loads being used when the residual fuel amount is less than the predetermined value, and the control apparatus sends such a control signal to a corresponding one of the drive devices that power is fed to one of the plurality of electrical loads, of which driving is directed by one of the direction devices, with a power feeding decrease rate preset and stored in the memory, corresponding to the electrical load, if the residual fuel amount detected by the fuel amount detector is less than the predetermined value.
As mentioned above, if at least one of the direction devices indicates the state transition from a stopping state to an operation state, the control apparatus sends such a control signal to a corresponding one of the drive devices that power is fed to a corresponding one of the electrical loads with a power feeding increasing rate preset and stored in the memory, corresponding to the electrical load. Thus, power is fed to the electrical load with the preset power feeding increase rate from the power source. That is, when starting of an electrical load is directed by one of the direction devices manipulated by an operator, power feeding to the electrical load starts and the ratio of the power feeding gradually increases. Therefore, at the stating state of an electrical load, because it hardly happens that the generator rapidly increases the generated power, and puts a rapid load on the engine, the engine speed can be kept stable.